1. Field of the Invention
The present invention relates to an improvement in an apparatus intended to fell and delimb trees in order to delimb said trees in length. Furthermore, the invention relates to a method of use of the aforesaid improved apparatus.
2. Description of the Prior Art
Since several years, forest and paper companies ought to adapt their exploitation policies toward the regeneration of forest and the protection of the environment. U.S. Pat. Nos. 3,981,336, 3,999,582 and 4,779,654 describe felling and delimbing apparatuses of the type comprising a vehicle provided with booms or levers and with a felling and delimbing head. In each of these patents, the felling and delimbing head is provided with means for driving the trunk of a tree along a longitudinal axis of the head and bringing branches against delimbing knives of said head. However, prior art apparatuses cannot delimb trees in length, they delimb a segment of the trunk and cut the delimbed segment to define a log of 4, 8 or 12 feet, and repeat the operation until the top of the tree is reached. Furthermore, the mounting of driving means on the felling and delimbing head, on one hand, generate a substantial increase of weight for said head and involve the use of strong booms or levers, and on the other hand, increase the risk of mechanical failure of said driving means because it is known that felling and delimbing head are subjected to very tough conditions. In the province of Quebec (CANADA), for example, 80% of forest companies are processing trees in length rather than in logs of 4,8 or 12 feet. Therefore, because actual felling and delimbing apparatuses do not allow to process trees in length in the forest, forest companies are actually delimbing trees along access roads with delimbing apparatuses of the type described in U.S. Pat. Nos. 4,919,715, 4,922,976 and 4,981,163. Therefore, the processing of wood always involve a succession of operations, that is: Felling trees; Carrying felled trees along an access road; delimbing trees along said access roads; optionally cutting trunks in logs; loading trucks with trunks or logs. Delimbing operations generate a gathering of branches along access roads and forest companies have to dispose of them (by burning or spreading) in order to facilitate subsequent silviculture works. Also, carrying whole trees in forest to an access road increases exploitation costs.
Therefore, there is a strong need for a felling and delimbing apparatus allowing to delimb trees in length on the site.